Democrats messed up when they created the mandate that everyone buy private health insurance, and they know it, argues Georgetown law professor Randy Barnett in The Wall Street Journal. When they realized that their constitutional rationale — Congress' power to regulate interstate commerce — wouldn't pass muster, they started describing it as a tax. It isn't, Barnett says, and the courts won't fall for this slight of hand:

"A 'tell' in poker is a subtle but detectable change in a player's behavior or demeanor that reveals clues about the player's assessment of his hand. Something similar has happened with regard to the insurance mandate at the core of last month's health reform legislation. Congress justified its authority to enact the mandate on the grounds that it is a regulation of commerce. But as this justification came under heavy constitutional fire, the mandate's defenders changed the argument—now claiming constitutional authority under Congress's power to tax.

This switch in constitutional theories is a tell: Defenders of the bill lack confidence in their commerce power theory. The switch also comes too late...."